[Dxspider-support] dxspider in docker and some questions on why some things are the way they are

[Brendan Minish]

I have been working on setting up spider so it can be run in a docker
container, mainly as an exercise in learning how to use docker well
enough to win arguments with bright eyed and bushy tailed 'Devops' types
who think ageing linux sysadmins are holding back progress..  

Running spider in docker is dead easy if you treat the docker instance
as a traditional virtual machine and go through the manual install
steps, however this is not the docker way and one misses out on a lot of
the shiny bits. 
Instead you build your image when you need it as a recipe from a Docker
file. 

Creating this recipe got me to thinking about some of the things around
how we install spider, hence the questions.. 

I'd also like to properly write up the installing on centos7
instructions on the Wiki 

1/ at install time we add a group 'sysop' for spider, this seems
redundant since a group called spider will be created and associated
with the spider user when we create the spider user with 'adduser'.
Is this now a Historical legacy ?
If there's a 3rd party application that really needs to access the files
owned by the sysop then it can be given group access to the sysop group

2/ we 'fix up' the permissions by doing 
     # chown -R sysop.spider spider
     # find . -type d -exec chmod 2775 {} \;
     # find . -type f -exec chmod 775 {} \; 

In all my recent installs 'git clone' has done the right thing with
similarly permissive permissions, this this seems unnecessary now that
we source dxpsider from a version control system rather than a tarball.

3/ in parts of the code spider references it's working directory
as /spider thus mandating the symbolic link be created.
ln -s  ~/sysop/spider /spider 
is there a good reason that the code does this instead of just
referencing via the current home directory of the user running spider
(Line 20 of spider/perl/cluster.pl , could it be altered to root =
"~/spider" ?)

 

4/ is there a way to execute 'set/spider <nodecall> ' without having to
invoke the console (or log in as sysop) to do so?
The reason I ask this is that setting a peer as a node has to be done
before you connect to it as a cron job.
Having to connect to the console and issue 'set/spider <nodecall>' is
the only step that prevents me creating a docker recipe that completely
automates firing up a cluster instance     
 

-- 
73
Brendan EI6IZ